1. Field of the Invention
The present invention relates to a type of potassium titanate for use as an additive and the like to be added to plastics, frictional materials, paints, lubricants, heat resistant materials, heat insulation materials or paper. More specifically, the present invention relates to a non-fibrous potassium titanate with a characteristic shape significant for health and hygiene, such that no hazardous effect might be caused even if a person inhales the potassium titanate; and a method for producing the same.
2. Description of the Related Art
Potassium titanate is generally in the form of fiber, and is practically used widely as an additive for improving the performance in the fields of plastics, paints, frictional materials and the like. However, fibrous powder is characteristically so bulky with poor fluidity that such powder is handled with much difficulty. Furthermore, fibrous powder readily generates powdery dust, disadvantageously from the respect of industrial environment.
For example, the carcinogenicity of asbestos has been drawing concern, and it is suggested that the carcinogenicity has some relation with the fibrous shape thereof. According to the hypothesis of Stanton, a fiber at a fiber diameter of 0.25 .mu.m or less and a length of 8 .mu.m or more has higher carcinogenicity. According to the International Labor Organization (ILO), furthermore, a fiber at a diameter of 3 .mu.m or less and a length of 5 .mu.m or more with a ratio of the length and the diameter being 3:1 or more is defined as an respirable fiber.
It is not elucidated yet as to the possibility that the fiber of potassium titanate affects the health of for example respiration system. In any way, less respirable fiber is desirable.
Because potassium titanate is so bulky with poor fluidity, however, the smooth feeding thereof is difficult, causing the attachment of the powder onto the wall of a feeding conduit to occlude the conduit, disadvantageously. Because of such phenomenon, the micro-pulverization thereof induces prominent cost escalation, so that it is difficult to produce industrially such micro-pulverized powder.